An armrest is used to be mounted on a seat frame of a vehicle, such as automobile. When the armrest is not in use, an arm is pushed upward to be stored beside a backrest of a seat, and when in use, the arm is pushed forward with respect to the seat to a substantially horizontal position.
Unexamined Japanese Patent Application Kokai Publication No. 2007-185223 discloses an armrest including a drum mounted on a seat frame, and an arm having a through hole into which the drum is inserted.
The arm is made of a metal plate having a thickness of 1.6 mm, and has, at an opening of the through hole, an annular ring formed by folding the metal plate. The drum comprises a body formed to have an outer diameter substantially identical to an outer diameter of the ring, and a head formed to have an outer diameter substantially identical to an inner diameter of the ring. In the armrest, the head of the drum is inserted in to the ring, and the arm pivots about the drum.